The Institut Laue–Langevin (ILL) is an internationally financed scientific facility, situated in Grenoble, France. It is one of the world centres for research using neutrons. Founded in 1967 and honouring the physicistsMax von Laue and Paul Langevin, the ILL provides one of the most intense neutron sources in the world and the most intense continuous neutron flux in the world in the moderator region: 1.5×1015 neutrons per second per cm2, with a thermal power of 58.3 MW.

The ILL neutron scattering facilities provide an indispensable analytical tool for the analysis of the structure of novel conducting and magnetic materials for future electronic devices, the measurement of stresses in mechanical materials, and investigations into how complex molecular assemblies behave, particularly in a biological environment. The ILL also tackles questions relating to the fundamental properties of matter.

The institute was founded by France and Germany, with the United Kingdom becoming the third major partner in 1973. These partner states provide, through Research Councils, the bulk of its funding. Ten other countries have since become partners. Scientists of institutions in the member states may apply to use the ILL facilities, and may invite scientists from other countries to participate. Experimental time is allocated by a scientific council involving ILL users. The use of the facility and travel costs for researchers are paid for by the institute. Commercial use, for which a fee is charged, is not subject to the scientific council review process. Over 750 experiments are completed every year, in fields including magnetism, superconductivity, materials engineering, and the study of liquids, colloids and biological substances.

Inside the reactor hall

The high-flux research reactor produces neutrons through fission in a specially designed, compact-core fuel element. Neutron moderators cool the neutrons to useful wavelengths, which are then directed at a suite of instruments and used to probe the structure and behaviour of many forms of matter by elastic and inelastic neutron scattering, and to probe the fundamental physical properties of the neutron. Nothing goes to waste: Fission products and gamma rays produced by nuclear reactions in the reactor core are also used by specialised instruments, which forms an important part of the instrument suite.

An ambitious modernisation programme was launched in 2000, through the design of new neutron infrastructure and the introduction of new instruments and instrument upgrades. The first phase has already resulted in 17-fold gains in performance. The second phase has started in 2008, it comprises the building of 5 new instruments, the upgrade of 4 others, and the installation of 3 new neutron guides.